Tweed Squares

Ingredients

• Cake:
• 2 egg whites
• 1/2 cup unsalted butter
• 2/3 cup white sugar
• 1 1/3 cups all-purpose flour
• 2 teaspoons baking powder
• 1 teaspoon salt
• 1/2 cup whole milk
• 1 teaspoon vanilla extract
• 1/2 cup miniature semisweet chocolate chips
• Frosting:
• 1/3 cup butter, softened
• 1 1/2 cups confectioners’ sugar
• 2 egg yolks
• 1 teaspoon vanilla extract
• 1 pinch salt
• Topping:
• 3 (1 ounce) squares semisweet chocolate
• 2 tablespoons butter

Directions

Preheat oven to 350 degrees F (175 degrees C). Grease a 9×9-inch square cake pan.

Beat egg whites in a glass or metal bowl until stiff peaks form. Lift your beater or whisk straight up: the egg whites will form sharp peaks.

Beat unsalted butter and white sugar together in a large bowl with an electric mixer until light and fluffy; beat in flour, baking powder, and 1 teaspoon salt. Beat milk and 1 teaspoon vanilla extract into flour mixture; fold in beaten egg whites and chocolate chips. Spread batter into prepared pan.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 25 minutes. Cool completely in the pan on a wire rack, about 30 minutes.

Beat 1/3 cup butter, confectioners' sugar, egg yolks, 1 teaspoon vanilla extract, and the pinch of salt together with an electric mixer until smooth; spread on the cooled cake.

Melt chocolate squares with 2 tablespoons butter in a microwave-safe bowl, about 30 seconds on High. Allow chocolate mixture to cool slightly, then spread chocolate carefully over iced cake. Refrigerate cake until chocolate is set, about 30 minutes.